Friday, June 27, 2008

What Really Happens to Skin When We Exfoliate

Most of my readers know about the importance of routine exfoliation, especially as far as using a well-formulated AHA or BHA product is concerned. The benefits are apparent within days of use, and skin continues to improve with ongoing use. But what’s actually occurring when we apply an exfoliant?

Well, it depends on what method of exfoliation you use! Generally speaking, the concept is that the top dead layer of normal skin (called the stratum corneum) sheds on a regular basis (thousands and thousands of skin cells every few minutes). This shedding process is due to the physiology of skin (how skin cells function and grow). New skin cells are produced in the lower layers of skin (the stratum basal layer); they then move to the surface, changing shape as they go, eventually dying and forming the outer, protective layer of skin. These dead skin cells on the surface are eventually shed as other cells from the lower layers travel to the surface and push them off, creating new “dead” layers of skin each time.

When we are young skin cells are regenerated and turn over very quickly, about once a week for children. As you age, the rate of skin cell renewal changes ranging from about every three weeks through our teens and 20s, and then it slows as we age with the rate varying depending on the shape of skin (primarily meaning skin that hasn’t been sun damaged or lost estrogen). Sun damage and stages of menopause reduces the ability of skin cells to reproduce in a healthy normal manner. Other than being smart about sun protection, considering various options of hormone replacement therapy, using skin care products laden with antioxidants and cell-communicating ingredients, or using a prescription retinoid such as tretinoin there isn’t much else that can help improve cell production.

Separate from the regeneration of skin cells in the lower layers of skin, the shedding process on the surface of skin can also become inefficient causing a build up of skin on the surface. Sun damage, loss of estrogen, dry skin, oily skin, and disorders such as psoriasis or rosacea can all effect how “smoothly” this natural exfoliation process takes place. When normal or healthy exfoliation doesn’t happen, skin can become rough, scaly, thickened, discolored, and look more lined. Different forms of exfoliation help to remove the built up outer layer of skin to uncover a more normal, “younger” looking layer hiding beneath. The most effective skin-care options for helping skin with this essential function are a well-formulated (meaning pH-correct) alpha hydroxy acid (AHA—the ingredient on the label would be glycolic acid, lactic acid, or gluconoalactone) or beta hydroxy acid (BHA—salicylic acid is the only BHA ingredient).

AHAs and BHA are available from several cosmetic brands, including my line. Using such products on a routine basis (which for some may mean once or twice daily, others every other day, or just twice per week) helps loosen and dissolve overly thickened, built-up, stagnant dead skin cells that are getting in the way of the healthier skin cells underneath. An AHA or BHA product, or even a topical scrub (though this is far less effective due to the way it abrades skin), hastens the removal of these dead skin cells.

When we help the outer layer of skin function more normally, your face can truly look younger. The best analogy I can think of is to compare it to the heels of your feet. Before you get a pedicure the built-up dead layer of skin on your heels looks dry, rough, discolored, scaly, and lines are pronounced. Once that layer is removed, and it can be removed fairly aggressively without damaging anything, your heels look much better. Moreover, once you apply moisturizer, which can now absorb better because it hasn’t been blocked by the proliferation of overproduced skin cells, viola—you have “younger”-looking feet. I’m not suggesting we should be that aggressive from the neck up or on most parts of your body, but the same benefit of exfoliating the feet holds true for the face, you just have to be gentler than you are with your heels.

Exfoliation for facial skin can also unclog pores by keeping dead skin cells from blocking the pore opening so sebum (oil) can flow more normally, which helps reduce blemishes and blackheads and it also allows antibacterial agents penetrate to where the bacteria causing acne is hiding.

What about exfoliating too often? Does it hinder or harm cell production?

Some of you have asked me about something known as the Hayflick Limit. The Hayflick response is a phenomenon that explains how many times skin cells will be reproduced. There seems to be a preset genetic determination of the number of times a skin cell will be regenerated. This turnover limit is only about what happens in the lower layer of skin where skin cells are produced (the basal layer). What happens on the surface in regard to exfoliation doesn’t affect the number of times new skin cells are created. Exfoliation is strictly about the dead surface layer of skin and that doesn’t get anywhere near the lower layers where new skin cells are being reproduced. Removing top layers of skin doesn’t cause new skin cells to be formed; the two functions are not related. So you don’t need to worry about damaging new skin cells by using topical exfoliants. You do want to be careful to avoid exfoliants that are too strong or too abrasive because of the irritation and inflammation such products cause; this can harm skin more than help it, but that still doesn’t affect cell regeneration.

You may have heard or read that some cosmetic companies are proclaiming people should stop exfoliating skin. The reasoning is that by doing so you hold on to your epidermal (surface) cells longer, which creates a more youthful look. My response to any company recommending this course of action is that they don’t know what they are talking about. There is no reason to preserve our epidermal cells (the outer layers of skin), they die and shed normally! Routine exfoliation just helps them do it in a healthier, more normal manner. What they are confusing is the notion of wanting to preserve the basal layer of skin where skin cells are regenerated, but that is a genetic trigger and not something related in any way to how the surface of skin functions. If there is research showing that exfoliation changes cell regeneration I have never seen it, but I have seen lots of research showing that exfoliation is incredibly beneficial for skin. There is even research showing glycolic acid can reduce skin cancer occurrences, which is astounding.

For the health and appearance of your skin exfoliation is a key component. It is necessary for most all skin types and is as basic as a gentle cleanser, sunscreen, and the need for skin to get topically applied antioxidants and cell communicating ingredients!

Thank you, Paula!

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